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Implementation of a particle-in-cell method for the energy solver in 3D spherical geodynamic modeling
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作者 Hao Dong ZeBin Cao +4 位作者 LiJun Liu YanChong Li SanZhong Li LiMing Dai XinYu Li 《Earth and Planetary Physics》 EI CAS CSCD 2024年第3期549-563,共15页
The thermal evolution of the Earth’s interior and its dynamic effects are the focus of Earth sciences.However,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially i... The thermal evolution of the Earth’s interior and its dynamic effects are the focus of Earth sciences.However,the commonly adopted grid-based temperature solver is usually prone to numerical oscillations,especially in the presence of sharp thermal gradients,such as when modeling subducting slabs and rising plumes.This phenomenon prohibits the correct representation of thermal evolution and may cause incorrect implications of geodynamic processes.After examining several approaches for removing these numerical oscillations,we show that the Lagrangian method provides an ideal way to solve this problem.In this study,we propose a particle-in-cell method as a strategy for improving the solution to the energy equation and demonstrate its effectiveness in both one-dimensional and three-dimensional thermal problems,as well as in a global spherical simulation with data assimilation.We have implemented this method in the open-source finite-element code CitcomS,which features a spherical coordinate system,distributed memory parallel computing,and data assimilation algorithms. 展开更多
关键词 numerical oscillation overshooting and undershooting particle-in-cell method three-dimensional spherical geodynamic modeling energy solver finite element method
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Three-dimensional magnetotelluric modeling in the spherical and Cartesian coordinate systems:A comparative study
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作者 Qi Han XiangYun Hu 《Earth and Planetary Physics》 CAS CSCD 2023年第4期499-512,共14页
With the increase in the coverage area of magnetotelluric data,three-dimensional magnetotelluric modeling in spherical coordinates and its differences with respect to traditional Cartesian modeling have gradually attr... With the increase in the coverage area of magnetotelluric data,three-dimensional magnetotelluric modeling in spherical coordinates and its differences with respect to traditional Cartesian modeling have gradually attracted attention.To fully understand the influence of the Earth’s curvature and map projection deformations on Cartesian modeling,qualitative and quantitative analyses based on realistic three-dimensional models need to be examined.Combined with five representative map projections,a type of model conversion method that transforms the original spherical electrical conductivity model to Cartesian coordinates is described in this study.The apparent resistivity differences between the spherical western United States electrical conductivity model and the corresponding five Cartesian models are then compared.The results show that the cylindrical equal distance map projection has the smallest error.A meridian convergence correction resulting from the deformation of the map projection is introduced to rotate the Cartesian impedance tensor from grid north to geographic north,which reduces differences from the spherical results.On the basis of the magnetotelluric field data,the applicability of the Cartesian coordinate system to western and contiguous United States models is quantitatively evaluated.Precise interpretations of the contiguous United States model were found to require spherical coordinates. 展开更多
关键词 spherical magnetotelluric modeling model conversion realistic electrical conductivity model quantitative evaluation
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Numerical Modeling of a Spherical Buoy Moored by a Cable in Three Dimensions 被引量:3
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作者 ZHU Xiangqian YOO Wan-Suk 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第3期588-597,共10页
Floating facilities have been studied based on the static analysis of mooring cables over the past decades. To analyze the floating system of a spherical buoy moored by a cable with a higher accuracy than before, the ... Floating facilities have been studied based on the static analysis of mooring cables over the past decades. To analyze the floating system of a spherical buoy moored by a cable with a higher accuracy than before, the dynamics of the cables are considered in the construction of the numerical modeling. The cable modeling is established based on a new element frame through which the hydrodynamic loads are expressed efficiently. The accuracy of the cable modeling is verified with an experiment that is conducted by a catenary chain moving in a water tank. In addition, the modeling of a spherical buoy is established with respect to a spherical coordinate in three dimensions, which can suffers the gravity, the variable buoyancy and Froude-Krylov loads. Finally, the numerical modeling for the system of a spherical buoy moored by a cable is established, and a virtual simulation is proceeded with the X- and Y-directional linear waves and the X-directional current. The comparison with the commercial simulation code Proteus DS indicates that the system is accurately analyzed by the numerical modeling. The tensions within the cable, the motions of the system, and the relationship between the motions and waves are illustrated according to the defined sea state. The dynamics of the cables should be considered in analyzing the floating system of a spherical buoy moored by a cable. 展开更多
关键词 numerical modeling dynamic simulation spherical buoy mooring cable dynamics of cable
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Establishment of European Regional Ionosphere Model Based on Spherical Harmonic Functions 被引量:1
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作者 Mingze Zhang 《Journal of World Architecture》 2021年第6期5-9,共5页
In order to study the temporal and spatial variation characteristics of the regional ionosphere and the modeling accuracy,the experiment is based on the spherical harmonic function model,using the GPS,Glonass,and Gali... In order to study the temporal and spatial variation characteristics of the regional ionosphere and the modeling accuracy,the experiment is based on the spherical harmonic function model,using the GPS,Glonass,and Galileo dual-frequency observation data from the 305th-334th day of the European CORS network in 2019 to establish a global ionospheric model.By analyzing and evaluating the accuracy of the global ionospheric puncture points,VTEC,and comparing code products,the test results showed that the GPS system has the most dense puncture electricity distribution,the Glonass system is the second,and the Galileo system is the weakest.The values of ionospheric VTEC calculated by GPS,Glonass and Galileo are slightly different,but in terms of trends,they are the same as those of ESA,JPL and UPC.GPS data has the highest accuracy in global ionospheric modeling.GPS,Glonass and Galileo have the same trend,but Glonass data is unstable and fluctuates greatly. 展开更多
关键词 Global ionosphere VTEC spherical harmonic function model
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Analysis of Error Caused by Replacing Spherical Shell with an Elastic Plate Model in Studying Bending Deformation of the Lithosphere
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作者 Wu Hongling Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081 Wang Ren Center for Geodynamics Research, Peking University, Beijing 100871 《Journal of Earth Science》 SCIE CAS CSCD 1998年第2期3-7,共5页
To study the bending deformation of the lithosphere, the simplification of replacing a spherical shell by a plate model is usually made. Based on the differential equations for the bending of plates and shallow spheri... To study the bending deformation of the lithosphere, the simplification of replacing a spherical shell by a plate model is usually made. Based on the differential equations for the bending of plates and shallow spherical shells, an expression for the error caused by such a simplification is derived in this paper. The effect of model sizes on the error is discussed. It is proved that if we replace the shallow spherical shell by a plate model to solve the bending deformation of lithospheric plate, a large error will be caused. In contrast, if we use a plate on an elastic foundation instead, an approximate solution closer to that of spherical shell can be obtained. In such a way, the error can be reduced effectively and the actual geological condition can be modeled more closely. 展开更多
关键词 plate model spherical shell model earth curvature bending deformation of lithosphere.
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Spherical cap harmonic analysis of regional magnetic anomalies based on CHAMP satellite data 被引量:6
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作者 Feng Yan Jiang Yong +6 位作者 Jiang Yi Liu Bao-Jia Jiang Jin Liu Zhong-Wei Ye Mei-Chen Wang Hong-Shen Li Xiu-Ming 《Applied Geophysics》 SCIE CSCD 2016年第3期561-569,582,共10页
We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface (307.69 km) and constructed a... We used CHAMP satellite vector data and the latest IGRF12 model to investigate the regional magnetic anomalies over China's Mainland. We assumed satellite points on the same surface (307.69 km) and constructed a spherical cap harmonic model of the satellite magnetic anomalies for elements X, Y, Z, and F over Chinese mainland for 2010.0 (SCH2010) based on selected 498 points. We removed the external field by using the CM4 model. The pole of the spherical cap is 36N° and 104°E, and its half-angle is 30°. After checking and comparing the root mean square (RMS) error of AX, AY, and AZ and X, Y, and Z, we established the truncation level at Kmax = 9. The results suggest that the created China Geomagnetic Referenced Field at the satellite level (CGRF2010) is consistent with the CM4 model. We compared the SCH2010 with other models and found that the intensities and distributions are consistent. In view of the variation off at different altitudes, the SCH2010 model results obey the basics of the geomagnetic field. Moreover, the change rate of X, Y, and Z for SCH2010 and CM4 are consistent. The proposed model can successfully reproduce the geomagnetic data, as other data-fitting models, but the inherent sources of error have to be considered as well. 展开更多
关键词 Geomagnetic model CHAMP satellite spherical cap harmonic model CM4 IGRF12
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A novel two-degree-of-freedom spherical ultrasonic motor using three travelling-wave type annular stators 被引量:6
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作者 王剑 胡锡幸 +1 位作者 王班 郭吉丰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1298-1306,共9页
In order to promote the tolerance and controllability of the multi-degree-of-freedom(M-DOF) ultrasonic motor, a novel two-degree-of-freedom(2-DOF) spherical ultrasonic motor using three traveling-wave type annular sta... In order to promote the tolerance and controllability of the multi-degree-of-freedom(M-DOF) ultrasonic motor, a novel two-degree-of-freedom(2-DOF) spherical ultrasonic motor using three traveling-wave type annular stators was put forward. Firstly,the structure and working principle of this motor were introduced, especially a spiral spring as the preload applied component was designed for adaptive adjustment. Then, the friction drive model of 2-DOF spherical motor was built up from spatial geometric relation between three annular stators and the spherical rotor which was used to analyze the mechanical characteristics of the motor.The optimal control strategy for minimum norm solution of three stators' angular velocity was proposed, using Moore-Penrose generalized inverse matrix. Finally, a 2-DOF prototype was fabricated and tested, which ran stably and controllably. The maximum no-load velocity and stall torque are 92 r/min and 90 m N·m, respectively. The 2-DOF spherical ultrasonic motor has compact structure, easy assembly, good performance and stable operation. 展开更多
关键词 two-degree-of-freedom ultrasonic motor spherical rotor friction drive model optimal control strategy
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Computation and analysis Computation and analysis of the geomagnetic field model in China and its adjacent area for 2003 被引量:1
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作者 顾左文 安振昌 +4 位作者 高金田 詹志佳 姚同起 韩炜 陈斌 《Acta Seismologica Sinica(English Edition)》 EI CSCD 2006年第2期145-154,共10页
Based on the geomagnetic data at 135 stations and 35 observatories in China in 2003, the Taylor polynomial model and the spherical cap harmonic model in China and its adjacent area for 2003 were established. In the mo... Based on the geomagnetic data at 135 stations and 35 observatories in China in 2003, the Taylor polynomial model and the spherical cap harmonic model in China and its adjacent area for 2003 were established. In the model calculation, the truncation order of the model and the influences of the boundary restriction on the model calculation were carefully analyzed. The results show that the geomagnetic data used are precise and reliable, and the selection of the truncation order is reasonable. The Taylor polynomial model and the spherical cap harmonic model in China and its adjacent area established in this paper are consistent very well. 展开更多
关键词 geomagnetic field model calculation Taylor polynomial model spherical cap harmonic model
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Internal co-seismic deformation and curvature effect based on an analytical approach
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作者 Jie Dong Wenke Sun 《Earthquake Science》 CSCD 2017年第1期47-56,共10页
In this study, we present a new method to compute internal co-seismic deformations of a homoge- neous sphere, based on our previous approach (Dong et al. 2016). In practical numerical computations, we consider a str... In this study, we present a new method to compute internal co-seismic deformations of a homoge- neous sphere, based on our previous approach (Dong et al. 2016). In practical numerical computations, we consider a strike-slip point source as an example, and compute the vertical co-seismic displacement on different internal spherical surfaces (including the Earth surface). Numerical results show that the internal co-seismic deformations are generally larger than that on the Earth surface; especially, the maximum co-seismic displacement appears around the seismic source. The co-seismic displacements are opposite in sign for the areas over and beneath the position of the seismic source. The results also indicate that the curvature effect of the internal deformation is pretty large, and larger than that on the Earth surface. The results indicate that the dislocation theory for a sphere is necessary in computing internal co-seismic deformations. 展开更多
关键词 Internal displacement. Curvature effect. spherical model
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Ray-optics model for optical force and torque on a spherical metal-coated Janus microparticle 被引量:4
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作者 Jing Liu Chao Zhang +2 位作者 Yiwu Zong Honglian Guo Zhi-Yuan Li 《Photonics Research》 SCIE EI 2015年第5期265-274,共10页
In this paper, we develop a theoretical method based on ray optics to calculate the optical force and torque on a metallo-dielectric Janus particle in an optical trap made from a tightly focused Gaussian beam. The Jan... In this paper, we develop a theoretical method based on ray optics to calculate the optical force and torque on a metallo-dielectric Janus particle in an optical trap made from a tightly focused Gaussian beam. The Janus particle is a 2.8 μm diameter polystyrene sphere half-coated with gold thin film several nanometers in thickness. The calculation result shows that the focused beam will push the Janus particle away from the center of the trap,and the equilibrium position of the Janus particle, where the optical force and torque are both zero, is located in a circular orbit surrounding the laser beam axis. The theoretical results are in good agreement qualitatively and quantitatively with our experimental observation. As the ray-optics model is simple in principle, user friendly in formalism, and cost effective in terms of computation resources and time compared with other usual rigorous electromagnetics approaches, the developed theoretical method can become an invaluable tool for understanding and designing ways to control the mechanical motion of complicated microscopic particles in various optical tweezers. 展开更多
关键词 Ray-optics model for optical force and torque on a spherical metal-coated Janus microparticle
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CDCC Approaches and Roles of Closed Channels in d-Nucleus Reactions
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作者 AN Hai-Xia CAI Chong-Hai 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期719-724,共6页
The effect of deuteron breakup in d-nucleus reaction is treated with the continuum discretized coupled channels (CDCC) approach, and the effects on the total reaction cross sections and elastic scattering angular di... The effect of deuteron breakup in d-nucleus reaction is treated with the continuum discretized coupled channels (CDCC) approach, and the effects on the total reaction cross sections and elastic scattering angular distributions are studied by comparing the calculations of CDCC and spherical optical model with our global deuteron optical potential [Phys. Rev. C 73 (2006) 054605] below 200 MeV, for target nuclei ranging from ^12C to ^208Pb. The contributions from the closed channels to the total reaction and breakup cross sections, and angular distributions of elastic scattering are also seriously discussed. 展开更多
关键词 CDCC approach closed channel spherical optical model global deuteron optical potential
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DESIGNATION AND APPLICATION OF A SPHERICAL LONG-WAVE SPECTRAL MODEL
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作者 吴国雄 《Acta meteorologica Sinica》 SCIE 1989年第2期132-144,共13页
A two-level,quasi-geostrophic long-wave model based on spherical coordinates was developed with the explicit part belonging to a low-order model.However,it includes not only diabatic heating,Ekman fric- tion and mount... A two-level,quasi-geostrophic long-wave model based on spherical coordinates was developed with the explicit part belonging to a low-order model.However,it includes not only diabatic heating,Ekman fric- tion and mountain distribution,but also parameterized forcing effects of transfer properties of transient eddies. Experiment results showed that,due to the introduction of the parameterization of transfer properties of transient eddies,remarkable improvements on characters of low-order model had been obtained.In addition to its economization in calculation and conciseness in physics as in a low-order model,the long- wave model was shown to describe the energetics and angular momentum balance of the atmosphere much more reasonably,and to present the features of zonal mean westerlies and stationary waves much more correctly than the corresponding low-order model.This kind of long-wave model was therefore regarded as suitable for theoretical research and numerical modelling of some aspects of the general circulation of the atmosphere. 展开更多
关键词 LOM MODE DESIGNATION AND APPLICATION OF A spherical LONG-WAVE SPECTRAL model GCM
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An engineering analysis of penetration of metal ball into fibre-reinforced composite targets
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作者 李永池 王志海 +2 位作者 王肖钧 胡秀章 Ren-huai LIU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第3期365-372,共8页
An engineering analysis of computing the penetration problem of a steel ball penetrating into fibre-reinforced composite targets is presented. Assume the metal ball is a rigid body, and the composite target is a trans... An engineering analysis of computing the penetration problem of a steel ball penetrating into fibre-reinforced composite targets is presented. Assume the metal ball is a rigid body, and the composite target is a transversely isotropic elasto-plastic material. In the analysis, a spherical cavity dilatation model is incorporated in the cylindrical cavity penetration method. Simulation results based on the modified model are in good agreement with the results for 3-D Kevlar woven (3DKW) composite anti-penetration experiments. Effects of the target material parameters and impact parameters on the penetration problem are also studied. 展开更多
关键词 fibre-reinforced composites engineering analysis transversely isotropic elasto-plastic materials spherical cavity dilatation model cylindrical cavity penetration model
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A one-way coupled atmospheric-hydrological modeling system with combination of high-resolution and ensemble precipitation forecasting 被引量:2
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作者 Zhiyong WU Juan WU Guihua LU 《Frontiers of Earth Science》 SCIE CAS CSCD 2016年第3期432-443,共12页
Coupled hydrological and atmospheric model- ing is an effective tool for providing advanced flood forecasting. However, the uncertainties in precipitation forecasts are still considerable. To address uncertainties, a ... Coupled hydrological and atmospheric model- ing is an effective tool for providing advanced flood forecasting. However, the uncertainties in precipitation forecasts are still considerable. To address uncertainties, a one-way coupled atmospheric-hydrological modeling sys- tem, with a combination of high-resolution and ensemble precipitation forecasting, has been developed. It consists of three high-resolution single models and four sets of ensemble forecasts from the THORPEX Interactive Grande Global Ensemble database. The former provides higher forecasting accuracy, while the latter provides the range of forecasts. The combined precipitation forecasting was then implemented to drive the Chinese National Flood Forecasting System in the 2007 and 2008 Huai River flood hindcast analysis. The encouraging results demonstrated that the system can clearly give a set of forecasting hydrographs for a flood event and has a promising relative stability in discharge peaks and timing for warning purposes. It not only gives a deterministic prediction, but also generates probability forecasts. Even though the signal was not persistent until four days before the peak discharge was observed in the 2007 flood event, the visualization based on threshold exceedance provided clear and concise essential warning information at an early stage. Forecasters could better prepare for the possibility of a flood at an early stage, and then issue an actual warning if the signal strengthened. This process may provide decision support for civil protection authorities. In future studies, different weather forecasts will be assigned various weight coefficients to represent the covariance of predictors and the extremes of distributions. 展开更多
关键词 one-way coupled hydrological and atmo- spheric modeling flood forecast high-resolution precipita-tion forecasting ensemble prediction
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